SIZING CLOSED CELL BACKER-ROD:Select a backer-rod diameter that is approximately 25% larger than the width of the joint.Joint WidthDiameter3/16" 1/4"1/4" 3/8"3/8" 1/2"1/2" 5/8"5/8" 3/4"3/4" 1"1" 1-1/4"1-1/4" 1-1/2"1-5/8 2"2" 2-1/2"2-1/2" 3"3-1/2" 4"APPLYING BACKER ROD:
1. Joint or opening should be clean and dry and free of all contaminates, loose materials, dry, and free of water or frost. 2. To install, compress backer-rod into the joint
before sealants are applied. Install backer-rod using a blunt tool or a plain faced roller.
3. Force the rod to the depth recommended by sealant manufacturer, (typically about 1/2 of joint width measured at the crown of the backer rod). A template or roller gauge may be used to control the depth at which the rod is placed.4. Don't stretch, puncture or tear backer-rod during installation
but gently force into the joint so that the backer-rod fits tight against the sides of the joint.